Interface optical phonon-assisted tunneling in double-barrier structures

Abstract

The phonon-assisted tunneling current in an asymmetric double-barrier structure is studied theoretically by considering the electron-interface optical-phonon interaction. The numerical results are obtained for the typical ${\mathrm{Al}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{A}\mathrm{s}/\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}/\mathrm{A}\mathrm{l}}_{y}{\mathrm{Ga}}_{1\ensuremath{-}y}\mathrm{As}$ structures and a new theoretical understanding about the experimental peaks of phonon-assisted tunneling current is proposed. It is found that only one phonon-assisted tunneling peak appears near the frequency of the well-longitudinal optical-phonon modes for the wider well case, and the contribution from the interface optical-phonon-assisted tunneling on the peak is dominant. The theory can explain the previous experimental results rationally.